The present invention relates to Viterbi decoding control, and more particularly, to a decoding circuit operating in response to decoded result and/or a plurality of Viterbi target levels with pattern dependency.
In an optical disc drive such as a Blu-ray Disc (BD) drive, Viterbi decoding is typically essential for decoding data. For example, a read path of the BD drive may comprise an optical pickup (OPU) module, a signal processing unit, an analog-to-digital converter (ADC), a finite impulse response equalizer (FIR EQ), a Viterbi decoder, and a data decoder. According to the related art, the Viterbi decoder does not always work properly, causing some problems such as data decoding fail. More specifically, in a situation where the disc accessed by the optical disc drive is not properly recorded, data decoding fail may occur due to improper Viterbi decoding control. In addition, in a situation where there are dusts or scratches on a disc accessed by the optical disc drive, similar problems may occur. A novel decoding circuit is therefore required to provide better Viterbi decoding control.